Update: This post has been updated to work with Oxygen Os 5.0 based on Android 8.0 Oreo and fix the DM-Verity warning via forced encryption disabler. There are total 3 methods using which you can Decrypt your Oneplus 3/3T phone. This also works on the previous Android 7.1 Nougat and the latest Open Beta.

The Device-Mapper-Verity (DM-Verity) error message can evolve while tinkering your device and flashing an unauthorized custom packages like a simple custom TWRP recovery. Now, since Android 4.4 and later the system has become more secure and the firmware verifies the boot through the dm-verity kernel feature. It simply checks the integrity of the device at start up. So if you flash a TWRP recovery or root the Android device, it throws a DM-Verity triggered error. Howeevr, this error can be easily fixed and the encryption can also be disabled.

Here in this guide we will show you how to fix DM-Verity warning on the Oneplus 3 or the OnePlus 3T on Android 7.0 Nougat. There are two methods through which you can remove the warning. The first one requires flashing the stock firmware and the second one is a easier one which will not require any flashing.

This tutorial will fix the DM-Verity issue. It will also decrypt your Android phone. Format the data into f2fs only as the latest official TWRP supports f2fs filesystem. Let’s get started.

Restart the phone into TWRP recovery. (Now, the DM- verity should be gone.)

Wipe the phone. Go to Advanced Wipe and wipe /data to f2fs (TAKE A LOOK HERE)

Reboot again to TWRP.

From TWRP go select the latest SuperSU zip file and flash it. If you have not placed the file in internal storage, access MTP and copy Super SU.zip into device and flash it.

Again wipe data and cache

Reboot to system.

Method 2: Flash the DM-Verity And Forced Encryption Disabler Zip

If you encounter DM verity updating from previous Oxygen OS to a new one, then follow this.

Flash the DM-Verity And Forced Encryption Disabler Zip

Clear the cache and dalvik

Reboot the system

Method 3: Disable Encryption and DM-Verity using Fastboot Commands

This is a simpler method and requires adb and fastboot environment on your PC. So, all you need to do is to head to the directory where you have installed the adb and fastboot tools. Now, hold shift and right click on the mouse and a popup menu will appear and then select “open command window here”. Ff you have already installed TWRP and dm-verity has been tripped at some point, simply reboot into fastboot mode on your phone and issue the following commands.

NOTE: Android USB Debugging should be on. You can switch that from Developer Settings on your phone. To do that head to Settings>About phone>Tap on Build number seven times and now the developer options will be unlocked & after that connect the phone to usb cable and follow the steps mentioned above.